Traditional approaches to producing furans from the C5 and C6 sugars of lignocellulosic biomass have several limitations which include high reaction temperatures and pressures, significant sugar loss to side-reactions, modest furan yields, and high purification costs. For instance, the production of furfural from concentrated xylulose (30 g/l) has not previously been achieved, likely due to the difficulty of producing relatively large quantities of high-purity xylulose in a cost-effective manner.
The two furans, hydroxymethyl furfural (HMF) and furfural, produced via the dehydration of the 6-carbon and 5-carbon sugars of lignocellulosic biomass, respectively, are projected to be in higher demand with their increasing use in petroleum refining, plastics, and the agrochemical and pharmaceutical industries. These furans are also versatile and platform chemicals for the synthesis of many useful products and fuels, including dimethyl/methylfurans, gasoline, and diesel components. However, both continuous and batch processes in commercial implementation are inefficient (less than 50% theoretical yield for furan) and are severely limited by side-reactions, in particular humin formation, that consume sugar as well as furans.
Thus, there is an unmet need for high-yielding methods of producing furans from biomass sugars.